Development and Validation of a Mixed Reality Configuration of a Simulator for a Minimally Invasive Spine Surgery Using the Workspace of a Haptic Device and Simulator Users

Most surgical simulators leverage virtual or bench models to simulate reality. This study proposes and validates a method for workspace configuration of a surgical simulator which utilizes a haptic device for interaction with a virtual model and a bench model to provide additional tactile feedback based on planned surgical manoeuvers. Numerical analyses were completed to determine the workspace and position of a haptic device, relative to the bench model, used in the surgical simulator, and the determined configuration was validated using device limitations and user data from surgical and nonsurgical users. For the validation, surgeons performed an identical surgery on a cadaver prior to using the simulator, and their trajectories were then compared to the determined workspace for the haptic device. The configuration of the simulator was determined appropriate through workspace analysis and the collected user trajectories. Statistical analyses suggest differences in trajectories between the participating surgeons which were not affected by the imposed haptic workspace. This study, therefore, demonstrates a method to optimally position a haptic device with respect to a bench model while meeting the manoeuverability needs of a surgical procedure. The validation method identified workspace position and user trajectory towards ideal configuration of a mixed reality simulator.

Comparison of Radiation Exposure of AIRO Intraoperative CT with C-Arm Fluoroscopy during Posterior Lumbar Interbody Fusion

Navigation systems used during minimally invasive spine procedures have evolved from uniplanar, two-dimensional C-arm fluoroscopy to multiplanar, 3D intraoperative computed tomography (iCT). In this study, the radiation exposure to the patient and operating room staff in posterior intervertebral lumbar fusion procedures is compared between iCT and C-arm fluoroscopy. The effective dose of the surgeon, operating nurse, and anesthesiologist was measured during surgery with personal dosimeters, and the effective dose of the patient was measured with GafchromicTM films. The time efficiency of the procedure was evaluated by recording the duration of pedicle screw fixation and the duration of the total surgery time. A total of 75 patients participated in the study; 30 patients had surgery guided by iCT and 45 by C-arm fluoroscopy. The radiation dose of the surgeon, the operating nurse, and the anesthesiologist was thirteen fold lower with surgeries assisted by iCT compared to C-arm fluoroscopy. In contrast, the effective dose of the patient significantly increased with iCT. Using iCT, radiation exposure of the operating room staff can be significantly reduced. iCT increases the effective dose of the patient and prolongs the operative time.

Application of a new percutaneous multi-function pedicle locator in minimally invasive spine surgery

In this study, a new percutaneous multi-function pedicle locator was designed for personalized three-dimensional positioning of a pedicle in minimally invasive spine surgery (MISS) without computer-assisted navigation technology. The proposed locator was used in a number of patients during MISS, and its advantages were analyzed. Based on the position of a pedicle determined by computed tomography (CT) and fluoroscopic images of a patient, 6 lines and 2 distances were used to determine the puncture point of a pedicle screw on skin, while 2 angles were used to indicate the direction of insertion of a pedicle guide needle from the patient's body surface. The results of the proposed locator were compared with those of the conventional freehand technique in MISS. The potential benefits of using the locator included enhanced surgical accuracy, reduced operation time, alleviation of the harmful intra-operative radiation exposure, lower costs, and shortened learning curve for young orthopedists.

Biomechanical Evaluation of the Effect of Minimally Invasive Spine Surgery Compared with Traditional Approaches in Lifting Tasks

Fusion of spinal vertebrae can be accomplished by different surgical approaches. We investigated Traditional Open Spine Surgery (TOSS) versus Minimally Invasive Spine Surgery (MISS). While TOSS sacrifices spine muscles originating or inserting on the affected vertebrae, MISS seeks to minimize the approach-related morbidity and preserve the tendon attachments of the muscles in the area. We captured 3-D motions of the full body of one healthy subject performing a variety of 10 kg box lifting operations representing activities-of-daily-living that are likely to challenge the spine biomechanically. The motion data were transferred to a full-body biomechanical model with a detailed representation of the biomechanics of the spine, and simulations of the internal spine loads and muscle forces were performed under a baseline configuration and muscle configurations typical for TOSS respectively MISS for the cases of L3/L4, L4/L5, L5/S1, L4/S1 and L3/L5 fusions. The computational model was then used to investigate the biomechanical differences between surgeries. The simulations revealed that joint reaction forces are more affected by both surgical approaches for lateral lifting motions than for sagittal plane motions, and there are indications that individuals with fused joints, regardless of the approach, should be particularly careful with asymmetrical lifts. The MISS and TOSS approaches shift the average loads of different muscle groups in different ways. TOSS generally leads to higher post-operative muscle loads than MISS in the investigated cases, but the differences are smaller than could be expected, given the differences of surgical technique.

Robotic-Assisted Trajectory Into Kambin's Triangle During Percutaneous Transforaminal Lumbar Interbody Fusion—Initial Case Series Investigating Safety and Efficacy

BACKGROUND Minimally invasive spine surgery (MISS) has the potential to further advance with the use of robot-assisted (RA) techniques. While RA pedicle screw placement has been extensively investigated, there is a lack of literature on the use of the robot for other tasks, such as accessing Kambin's triangle in percutaneous lumbar interbody fusion (percLIF). OBJECTIVE To characterize the surgical feasibility and preliminary outcomes of an initial case series of 10 patients receiving percLIF with RA cage placement via Kambin's triangle. METHODS We performed a single-center, retrospective review of patients undergoing RA percLIF using robot-guided trajectory to access Kambin's triangle for cage placement. Patients undergoing RA percLIF were eligible for enrollment. Baseline health and demographic information in addition to peri- and postoperative data was collected. The dimensions of each patient's Kambin's triangle were measured. RESULTS Ten patients and 11 levels with spondylolisthesis were retrospectively reviewed. All patients successfully underwent the planned procedure without perioperative complications. Four patients underwent their procedure with awake anesthesia. The average dimension of Kambin's triangle was 66.3 m2. With the exception of 1 patient who stayed in the hospital for 7 d, the average length of stay was 1.2 d, with 2 patients discharged the day of surgery. No patients suffered postoperative motor or sensory deficits. Spinopelvic parameters and anterior and posterior disc heights were improved with surgery. CONCLUSION As MISS continues to evolve, further exploration of robot-guided surgical practice, such as our technique, will lead to creative solutions to challenging anatomical variation and overall improved patient care.

Double tubular minimally invasive spine surgery: a novel technique expands the surgical visual field during resection of intradural pathologies

OBJECTIVE A major challenge of a minimally invasive spinal approach (MIS) is maintaining freedom of maneuverability through small operative corridors. Unfortunately, during tubular resection of intradural pathologies, the durotomy and its accompanying tenting sutures offer a smaller operating window than the maximum surface of the tube’s base. The objective of this study was to evaluate if a novel double tubular technique could expand the surgical visual field during MIS resection of intradural pathologies. METHODS A total of 25 MIS resections of intradural extramedullary pathologies were included. A posterior tubular interlaminar fenestration was performed in all surgeries. A durotomy covering the whole diameter of the tubular base was the standard in all cases. After placement of two tenting sutures on each side of the durotomy and application of tension, the resulting surface of the achieved dura fenestration was measured after optical analysis of the intraoperative video. In the next step, a second tube, 2 mm thinner than and the same length as the first, was inserted telescopically into the first tube, resulting an angulated fulcrum effect on the tenting sutures. RESULTS Optical surface analysis of the dura fenestration before and after the second tubular insertion verified a significant widening of the visual field of 43.1% (mean 18.84 mm2, 95% CI 16.8–20.8, p value < 0.001). There were no ruptured tenting sutures through the increased tension. Postoperative MRIs verified complete resection of the pathologies. CONCLUSIONS Inserting a second tube telescopically during posterior minimally invasive tubular spinal intradural surgery leads to an angulated fulcrum effect on the dura tenting sutures which consequently increases the surface of the dura fenestration and induces a meaningful widening of the visual field.

Application of a Simulation System Using Augmented Reality to Practice the Skills of Minimally Invasive Spine Surgery

The developed HoloDoctor software package allows performing surgical operations in real time. It should be emphasized that the operation time on the HoloDoctor PC is reduced by 20-30% compared to traditional methods. The performance of HoloLens glasses with our program is high, while allowing the doctor to save time. The complex provides diagnostics, therapy planning, treatment adjustment as needed and minimizes the risk of medical error. HoloDoctor can be used in educational practice by integrating it into educational programs for medical specialties.